Magnetic false twist spindle

ABSTRACT

An improved magnetic false twist spindle comprising a tubular spindlette having a locking means for the false twist, a single driving roller attached to a driving shaft, said roller being capable of rotating at high speeds, and annular magnets, said magnets holding the spindlette against the driving roller such that the spindlette is centered axially and laterally. The improvement resides in that the annular magnets are coaxially located at the two ends of the driving roller and in close contact with the enveloping support of the spindle. The poles of the magnets are so located that a complete magnetic circuit results.

United States Patent Raschle [451 Feb. 1,1972

[54] MAGNETIC FALSE TWIST SPINDLE Primary ExaminerDonald E. WatkinsAttorney-Sherman and Shalloway [57] ABSTRACT An improved magnetic falsetwist spindle comprising a tubular spindlette having a locking means forthe false twist, a single driving roller attached to a driving shaft,said roller being capable of rotating at high speeds, and annularmagnets, said magnets holding the spindlette against the driving rollersuch that the spindlette is centered axially and laterally. Theimprovement resides in that the annular magnets are coaxially located atthe two ends of the driving roller and in close contact with theenveloping support of the spindle. The poles of the magnets are solocated that a complete magnetic circuit results.

2 Claims, 3 Drawing Figures PATENTED FEB 1 I972 E E H m A R F E w IATTORNEYS This invention relates to a novel magnetic false twist device.More particularly this invention relates to a magnetic false twistdevice in which the ill effects of Foucault currents are minimized.

False twist devices are often used in processes for producting texturedtextile yarns. Briefly false twisting comprises feeding the yarn intothe false twist device followed by passing the yarn through a heatingelement somewhat upstream from the false twist device so that it heatsthe yarn while it is in the false twisted state, and setting the falsetwist into the yarn during the subsequent cooling.

Since false twisting is such an important step in the production oftextured yams, numerous devices have been developed to impart a falsetwist to the yarn. Generally they comprise a tubular spindlette providedwith means to lock the twist and with means to rotate the spindlette.For a long time the rotating means was purely mechanical and comprisedvarious means to push the spindlette against a drive means such as abelt. Later false twist devices were designed which incorporated themagnetic holding of the spindlette against the drive means. Thesedevices are generally called magnetic false twist spindles. The firstmagnetic false twist spindle comprised a spindlette in contact with atleast two spools, these spools having end discs which are positionedparallel to each other,

and mounted on parallel axes which are close enough to each other so asto insure a certain amount of overlap of the end discs so that thespindlette was held against the rims of two pairs of overlapping enddiscs. A horseshoe magnet held the spindlette against these rims. Thisdevice was an important step forward in the art and allowed for the useof very high rotational speeds of the spindlettes, however, this devicehad one important drawback, the shearing forces created by the tworollers tended to wear the elastic covering on these rims. In view ofthis drawback a single roller-type magnetic false twist spindle wasdeveloped where the spindlette was attached magnetically by a horseshoemagnet against the discs of a single roller. This allowed the spindletteto flow freely without any support except for that created by the magnetacting on the ends of the spindlette which was axially and laterallycentered in the poles of the magnet. This type of device was a vastimprovement over the previous devices since the elastic coverings on therim wore more slowly and less power was needed to operate this device. Agreat number of different devices of this type all having magnets indifferent shapes have been developed. However, since the magnetic alloysare expensive and machining the same into intricate designs presents agreat number of problems, a simple shape for the magnet is preferable Itis therefore, not surprising that the use of annular magnets has beensuggested for use in a false twist spindle of the monoroller type.However, the use of annular magnets have had the disadvantage of a highpolar distance which causes a major loss of power of the magnetic field,and since the magnetic field is also closed through the rotating driveroller, Foucault currents cause harmful breaking effects. To overcomethis problem it has been suggested to mold the roller or the rims of theroller from a plastic material; however, due to the heat generated bythe Foucault currents this has not been successfully done.

Briefly, the magnetic single-roller false twist spindle of thisinvention comprises the single driving roller, a freely floatingspindlette, two annular magnets placed on the sides of the drivingroller in such a way that the spindlette is axially and laterallycentered by the magnetic system which acts directly on the ends of thespindlette, and an enveloping support, the improvement which comprisesplacing the two annular magnets on either side of the driving roller andin close contact with the support so as to close the magnetic circuitthrough the enveloping support.

It is therefore the primary object of this invention to provide animproved single-roller magnetic false twist spindle.

It is still a further object of this invention to provide an improvedsingle-roller magnetic false twist spindle wherein the polar distance ISgreatly reduced and the magnetic circuit is closed through theenveloping support so as to reduce the risk of generating Foucaultcurrents.

Further objects and advantages of the improved apparatus of thisinvention will become more apparent in the following more detaileddescription thereof. This description is intended to illustrate theimproved apparatus of this invention and is not intended to be[imitative but covers any and all the variations included within thescope of the appended claims.

FIG. 1 is a modified front view along line l-1 as shown in FIG. 2 of theimproved single-roller magnetic false twist device of this invention.This view illustrates the path of the magnetic circuit.

FIG. 2 is a side view of the magnetic single-roller false twist spindleof this invention.

FIG. 3 is a top view of the device of this invention.

Referring to FIGS. 1 and 2, the magnetic single-roller false twistdevice of this invention comprises a single driving roller 4 having twoend discs 14 and 24 so that rims as shown form a rolling contact for thetubular spindlette 5. Spindlette 5 may be provided with a middlecentering ring 35 and ends 15 and 25 which are constructed to roll onend discs 14 and 24. Spindlette 5 is also provided with a false twistdevice such as crossed bars. End discs 14 and 24 may be provided with anelastic covering, such as polyurethane, which is commonly used withmagnetic single-roller false twist spindles. These elastic covers arenot necessary, however, for the operation of this device. The drivingroller 4 is attached to drive shaft 6 which has a pulley or wheel 8 incontact with driving belt 9 which in turn is driven by a motor or someother device (not shown). Driving shaft 6 is supported by supportingmeans 7 and 17, such as ball bearings. On either side of driving roller4 are two split rings 10 and 11 which form the pole shoes of annularmagnets l and 2. Annular magnets l and 2 are so placed in envelopingsupport 3 so as to have contact with enveloping support 3. Magnets 1 and2 have opposing magnetic poles facing each other, i.e., magnet 1 has thenorth pole facing magnet 2s south pole. Referring to FIG. 3, thelocation of the slits 20 and 21 and split rings 10 and 11 is shown. Thespindlette should be centered between these slits. This system allowsfor the magnetic field to flow as shown in FIG. 1 by arrows l2 and 13.The magnetic field flows from magnet 1 through pole shoe 10 through thespindlette 5 to pole shoe 11 through magnet 2 and casing 3 back tomagnet 1, thus completing the circuit. This completed magnetic circuitholds the spindlette 5 against end discs 14 and 24 of driving roller 4.This reduces the distance between the slits to an absolute minimum.

The casing 3, spindlette 5 and pole shoes 10 and 11 should beconstructed out of a conductive material such as iron and other similarmetals and alloys. Furthermore, spindlette 5 should also be constructedout of easily magnetizable material so that it is easily held againstend discs 14 and 24. Spindlette 5 should also be provided with means tolock the false twist in the yarn to be textured while passing throughspindlette 5.

What is claimed is:

1. In a magnetic false twist spindle comprising a tubular spindlettehaving locking means for the false twist, a driving shaft, a singledriving roller attached to the driving shaft, said roller capable ofrotating at high speeds, a. pair of annular magnets which hold thespindlette axially and laterally centered against the single drivingroller and an enveloping support, the improvement which comprises theplacing of the annular magnets coaxially at the two ends of the drivingroller said magnets being positioned so that their opposite magneticpoles are facing and said magnet being in close contact with theenveloping support of the spindle so that a complete magnetic circuit isfonned.

2. The magnetic false twist spindle of claim 1 wherein the annularmagnets further comprise two split rings, said split rings being sopositioned that the center of the spindlette is between the lips of thesplit rings so that there is a minimum of distance between thespindlette and the lips of the split rings.

1. In a magnetic false twist spindle comprising a tubular spindlette having locking means for the false twist, a driving shaft, a single driving roller attached to the driving shaft, said roller capable of rotating at high speeds, a pair of annular magnets which hold the spindlette axially and laterally centered against the single driving roller and an enveloping support, the improvement which comprises the placing of the annular magnets coaxially at the two ends of the driving roller said magnets being positioned so that their opposite magnetic poles are facing and said magnet being in close contact with the enveloping support of the spindle so that a complete magnetic circuit is formed.
 2. The magnetic false twist spindle of claim 1 wherein the annular magnets further comprise two split rings, said split rings being so positioned that the center of the spindlette is between the lips of the split rings so that there is a minimum of distance between the spindlette and the lips of the split rings. 